Fuse



March 31. 1925. 1,531,756

L. F. ROACH ET AL FUSE Filed April 18. 1922 @wwwVoi/w Leshe 11 Ru 5 ch Mlchaal FAA/n11 a Patented li/lar. 31, I925.

STATES LESLIE F. RDACH AND MICHAEL F. WOLFE, OF SOUTH MILVTAUKEE, WISCONSIN.

FUSE.

Application filed. April 18, 1922.

To all whom it may concern:

Be it known that we, LESLIE F. RoAoir and MICHAEL E. WOLFE, both citizens of the United States, and residents of South Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Fuses; and we do hereby declare that the following is a full, clear, and exact description thereof.

The invention relates to fuses. It comprises a glass tube having a chamber therein partially filled with mercury into which rods are adaptedto project, the rods extending to contacts.

A primary object of the device is the provision of means operative to carry electric current but tending to throttle overcharges. The mercury vaporizes on overcharges or short circuits restricting the flow of current. On the removal of the overcharge, the mercury recondenses and falls between the contact rods operating again to transmit the current.

An important object is simplicity of operation and construction, the device being easy to manufacture and inexpensive, yet at all times reliable in operation.

With the above and other objects in view which will appear as the description proceeds, our invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claim, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claim.

In the accompanying drawing. we have illustrated one complete example of the physical embodiment of the present invention constructed according to the best mode we have so far devised for the practical application of the principles thereof, and in which:

Figure l is a central vertical section of a modification, and

Figure 2 is a side elevation, partly in section of a second modification.

In the modification shown in Figure 2, glass tube is provided with contact rings 11 of brass or similar material secured to the ends of the tube. Brass rods 12 and 13 Serial No. 554,714.

portions of rods 12 and 13. The current is transmitted to the mercury thru cont-act rings 11 and rods 12 and 13, and at normal rates of flow there is no impedance by the mercury. ()n the occurrence, however, of an overcharge or short circuit, the mercury 15 vaporizes and expands, filling the chamber 14 and restricting the flow of electric current.

In the modification shown in Figure l, the automatic fuse is shown as applied to a common screw in socket. Vitreous base 16 formed substantially into a cylinder, has metallic threads 17 on one end thereof, with which spring 18 is integral projecting into an opening 19. A similar spring 20 is secured by bolt 21 in opening- 22. The springs grip contact 23, with which rod 24;, projecting into chamber 25 and having its end submerged in mercury 26, is rigid. Rod 27 extends from the mercury to contact 28. Current is transmitted thru threads 17, spring 18, rods 24 and 27. mercury 26, and contact 28. The springs facilitate the ready insertion of glass tube 29, and retain it securely in place.

We claim:

The combination of an insulating body having an aperture therethrough, a metal ferrule surrounding av portion of said body and having threads thereon, said body having a slot extending radially outwardly from said aperture, a spring tongue located within said slot and rigidly joined to said metal ferrule, a glass plug adapted for insertion within said aperture, said plug having an integral cavity partially filled with mercury and having a terminal contact por tion, a conductor extending from said terminal contact portion inwardly into said mercury, a peripheral metal band surrounding said plug and adapted to contact with said spring tongue, and a conductor extending inwardly from said band and dipping into said mercury. I

In testimony that we claim the foregoing we have hereunto set our hands at South Milwaukee, in the county of Milwaukee and State of Wisconsin.

LESLIE F. ROACH. MICHAEL F. WOLFE. 

